Electric door-operator.



T. NAKAHARA.

ELECTRIC DOOR OPERATOR. APPLICATION FILED P212, 1910.

957,572, Patented May 10,1910.

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fi 0 M o w o w 1 ESSES: IIVVENTOR k m W strx'ras PATENT OFFICE.

'rorcn NAKAHARA, or NEW YORK, N. Y.

ELEGTIC DOOR-OPERATOR.

To all'whom'fit may concern:

Be it known that I, Town NAKAHARA, a subject of the Emperor of Japan, and resident'of the borough of Manhattan, 1n the city and county of New York and State of New York, have invented certain new and useful Improvements in Electric Door- .Operators, of which the following is a specification.

This invention relates to a means for causing a door to be mechanically opened and closed by an electric motor operating to open it, and a weight tending. to overhaul or reverse the motor thus operating to close it, and although approximations of this device have been known and developed in the past many of my best and most advantageous features were not a part of such approxi mations. v

I utilize the motor itself 'as the means for retaining the door in an open position, by the action of a fully magnetized field exerting its retarding and holding force upon :a short circuited armature. This principle is well known in electric traction apparatus and in elevators and hoists.

The principal features and advantages of my invention will develop in the specification andwhat I consider a desirable means of carrying out this invention follows in which: v I

Figure 1 is a diagrammatical view partly in elevation, of the complete apparatus and a door in connection with which is operates. Fig. 2 is on a larger scale it shows the field openin and closin switch.

Simi ar letters 0 reference indicate like parts wherever they appear.

As shown in the drawings, designed to operate with a sliding door and such a door is shown .at A in Fig. 1. The

door is, by the brackets A and the rollers A supported upon a track B, which is in turn attached to-a convenient support B which maybe the side wall through which the "door opening has been produced. The ordinary means as a handle A is provided for opening the door by hand and the closmg securedto the downwardly hanging end and is attache to the door at A The pulley C is rotatably mounted in a bracket G which bracket is in turn secured to a convenient Specification of Letters .Patent. Application filed February 2, 1910. Serial No. 341,453.

my device is means is secured to the door at a high point, in this instance at A A weighLC Patented May 10, 1910.

though stationary support, which may be the 'side wall or partition. At a convenient height, but to the edge opposite to that which the cable C isattached, a cable E is secured by means of a bolt or by other means. A motor of proper'size-tq perform the duties required, is arranged by being secured tothe side wall or other firm support, at a just sufiicient height to allow the cable E which E on the motor,

lane.

A plurality of switches which I will de scribe in detail later in the specification, I have shown as secured to the floor and immediately below the motor. They must be placed in line with the travel of the door, so that a projection A", which is also attached to the right edge of the door will .contact with the switches for a purpose which shall appear later.

A portion of the floor which I have indicated by K forms a hinged platform, to give an easy and not too great movement 'to the platform, I prefer to have this platform as wide as the door and have in my experiments "hinged the whole section of the floor, which is immediately below the door, when the door is in its closed position.

The electrical and electro-mechanical part of my device is somewhat complicated so I to travel in a horizontal will describe themby following the path of the current commencin with the uppermost line lead D, which is irectly connected to a block D which carries a contact screw D A spring switch D with the screw D andreceives current from is to be attached to the drum is normally in contact the line lead D. An, armature lead E of the shunt-wound motor E'is connected to the spring switch D and with one brush of the motor E. The other brush is, through the armature lead E connected to the spring switch F and this spring switch is in nor- Ibnal contact with a contact-screw F carried which is-connected to the block'F, has its other end attached to the stationary part of a spring switch G.

G indicates the spring or flexible member of the switch and to this member G2 a lead H- is attached. This lead H isthe other line lead, the spring G is normally in an open condition.

The fields ofthe motor E are connected independent of the armature circuit or switches. One of the field leads E -is dithe block F. A" lead G one end ofv rectly connecte'd to the line lead D, the, other -lead E is carried to a switch J located the trap K in an upward position level with the remainder of the floor, but when a weight as that of a person passing through the door is placed upon the trap K it causes one endof the trap to sink and brings the projection K into contact with the flexible member G of the switch G with the result that the circuit is closed through the switch, a

and through the line lead H and lead G thus to the armature. Another result of the depressed platform is that the blade J of the switch J is forced into contact with the terminal J 2 thus closing the field circuit of the motor E through the wire J and the field lead E. The motor revolvesand the cable E is wound upon the drum E drawing the door into an open position, this continues until a projection A on the door A strikes the spring switch F and forces it out of contact with the screw F The spring switch F barely leaves the screw F when it comes into intimate contact with the spring switch D through the close proximity of the blocks F D The spring switch D is forced out of contact with the screw 1) and the armature circuit is open and the armature stops revolving. It will.

be seen that as soon as the armature circuit is open, the armature is disconnected from the line, but almost at once the armature circuit is closed again upon itself, that is, it is short circuited. The field circuit remains complete and should the motor overhaul by the action of the weight C and thereby pay out the cable E to any extent, the projection A leaves the spring switch F and the armature circuit 'is immediately completed, with the result that the motor will again start and rewind the cable, this will occur as often as it is necessary to accomplish the result of retaining the door in an open position while a person is on the platform A It is sometimes desirable to cause the door to close slowly. I accomplish this by keeping a full field, or a complete field circuit through the motor even after a pedestrlan has left the platform K in fact until the projection A comes in contact with the adjustable'block J on the operating shaft J of the switch J;

The 'door closes through a greater or less 1 portion of the entire length of travel at the slow rate allowed by reversing the armature invention what I claim E being made with the block F or the stationary side of the switch G, this will cause the door to close more rapidly which may be an advantage in some instances.

This device may be worked as well on a swinging door.

Other modifications good mechanic.

Having carefully and fully described my and desire to secure may be made by a by Letters Patent is:

1. In a device of the character described, a door, a motor for operating said door, a flexible connection between said motor and said door, a weight arranged in opposition to said motor and flexibly connected to said door, a hinged platform beneath said door and a switch operated by said platform for starting said motor, means attached to said door for causing themotor to stop, and a double contact switch operated by said last named means for causing the motor to exert a holding motion upon said door.

2. In a device of the character described, in combination with a door, a motor for opening such door, a weight arranged in opposition to such motor for closing said door, means arranged below said door for automatically starting said motor, and an automatically operated switch for stopping said motor, said switch arranged to short circuit-the armature circuit by continuation of the movement thatstops the motor.

3. In a device of the character described, in combination with a door, a motor, a weight arranged in opposition to such motor, means below said door for starting said motor, an automatically 0 erated switch for stopping said-motor an short circuitin the armature thereof, and an additiona switch for closing the field of said motor and maintaining it closed'until the door has reached a predetermined point in its closing motion.

Signedat New York city in the county of New York and State of New York this 25th day of January A. D. 1910.

' TOICH NAKAHARA. 

